This research aims to comprehensively compare the clinical outcomes of first-line Afatinib and first-line Osimertinib in a real-world setting for patients meeting the Taiwan NHI reimbursement criteria for Osimertinib—advanced NSCLC with EGFR exon 19 deletion and no initial CNS metastasis. The gene discussed is EGFR; the disease is non-small cell lung carcinoma.